As an alternative to polyurethane, consider DELRIN material (Firm Feel offers the LCA bshgs in DELRIN).... far superior/durable, longer-lasting, won't deteriorate like poly eventually does, much less squeak. Also, try to install greaseable fittings where ever possible (most sellers... Firm Feel, PST, Hotchkis... have them for most applications). My leaf spring front poly bshgs squeak (no big deal, only at slow speeds can they be heard a little). And, consider occasionally replacing the sway bar end-link bshgs... they will deteriorate and break apart over time... that's why they sell replacements at the retail auto parts stores (AutoZone, Advance Auto Parts, O'Reiley's, etc).
